[CentOS] Ethernet puzzle

Ashley M. Kirchner

ashley at pcraft.com
Fri Dec 28 16:49:46 UTC 2012


     So I just finished doing a fresh install of CentOS 6.3.  The 
machine has three ethernet ports in it: one on the motherboard (VIA 
Rhine), and two add-on cards, an Intel Pro100 and an old SMC1255TX. When 
CentOS comes up, this is what I see in the dmesg output:

     # dmesg | grep eth
     e100 0000:00:08.0: eth0: addr 0xf6043000, irq 16, MAC addr 
00:02:b3:be:02:87
     eth1: ADMtek Comet rev 17 at MMIO 0xf6040000, 00:4c:69:6e:75:79, 
IRQ 17.
     udev: renamed network interface eth0 to rename2
     udev: renamed network interface eth1 to eth3
     udev: renamed network interface rename2 to eth1
     eth0: VIA Rhine II at 0xf6042000, 00:16:17:17:22:8e, IRQ 23.
     eth0: MII PHY found at address 1, status 0x786d advertising 05e1 
Link 45e1.
     eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
     eth0: no IPv6 routers present

     So, according to the musical playing going on there, the result is:

     eth0: VIA Rhine
     eth1: IntelPro 100 (originally comes up as eth0 but gets renamed eth1)
     eth3: SMC1255TX (originally comes up as eth1 but gets renamed eth3)

     Here's my issue:

     In udev rules (/etc/udev/rules.d/70-persistent-net.rules I see:

     # PCI device 0x1113:0x1216 (tulip)
     SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:4c:68:6e:ff:ff", ATTR{type}=="1",
     KERNEL=="eth*", NAME="eth2"

     # PCI device 0x8086:0x1229 (e100)
     SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:02:b3:be:02:87", ATTR{type}=="1",
     KERNEL=="eth*", NAME="eth1"

     # PCI device 0x1106:0x3065 (via-rhine)
     SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:16:17:17:22:8e", ATTR{type}=="1",
     KERNEL=="eth*", NAME="eth0"

     # PCI device 0x1113:0x1216 (tulip)
     SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:4c:69:6e:75:79", ATTR{type}=="1",
     KERNEL=="eth*", NAME="eth3"


     Question is, where did the first tulip interface come from? That's 
not any of the interfaces on the machine, it doesn't match the MAC 
address of any of the interfaces, so where'd it come from?

     Furthermore, when I look in 
/etc/sysconfig/network-scripts/ifcfg-eth2, the HWADDR there is the same 
as the first interface listed above.  But again, it's not in dmesg's 
output.  As far as I can tell, it's a ghost interface ...

     What gives, and how can I get rid of it so that the proper 
interface gets the eth2 spot?

     A



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